According to prior art, content delivered to a receiver in the context of content-on-demand such as video-on-demand (VoD) is delivered through a one-to-one connection with a VoD server, for example by using IP (Internet Protocol) unicast distribution. This one-to-one distribution model is opposed to a one-to-many distribution model, where a same digital content source is received at the same time by many receivers.
The one-to-one distribution model allows a receiver to intervene on the unrolling of the digital content by issuing so-called trick mode commands. Trick mode commands comprise actions such as play, stop, pause, fast reverse, fast forward a digital content and go to chapter in a digital content. In this distribution model, it is the receiver that commands the streaming of a digital content through a one-to-one connection with a digital content server. While this distribution model allows trick mode commands, the model does not allow for synchronization between receivers, that is: rendering a same image from a same digital content stream at the same time on different receivers.
In the one-to-many distribution model, it is the distribution server that commands the digital content streaming. The one-to-many distribution model is used to distribute a same digital content stream to a large audience, for example to distribute TV or radio programs. With this distribution model, trick mode commands are not allowed, or only allowed for one receiver. Synchronization between the digital content streams distributed over receivers is inherent to the distribution model, because a same digital content stream is delivered at the same time to many receivers, for example by using IP multicast distribution.
The above described distribution models are convenient for Video-on-Demand applications and digital content or television broadcasting. However, the above described distribution models do not allow combining a one-to-many distribution with the support of trick mode commands from several receivers. One of the problems that need to be solved when trick mode commands from several receivers are to be supported in a one-to-many digital content stream distribution model is the synchronization of the rendering of images from the digital content stream between the receivers.
According to prior art, synchronization of rendering of a digital content over multiple receivers with support of trick mode commands is applied in the context of, for example, e-learning applications, where students each have a receiver and can issue trick mode commands to intervene on the unrolling of a course. According to prior art, the course is distributed through prior downloading on the receiver of each student, and synchronization of the content rendering between receivers is done by synchronization of the playback of the locally stored digital contents. However, synchronizing the rendering of a digital content amongst receivers that have the digital content stored locally is not the same thing as synchronizing the rendering of a digital content that is streamed from a central source.
Current state of the art does not allow a one-to-many digital content stream distribution with support of trick mode commands and synchronized digital content rendering.